export function MP(ak) { 
    return new Promise(function (resolve, reject) {
      window.onload = function () {
        resolve(BMap) 
      } 
      var script = document.createElement("script");
      script.type = "text/javascript"; 
      script.src = "http://api.map.baidu.com/api?v=2.0&ak="+ak+"&callback=init";
      script.onerror = reject; 
      document.head.appendChild(script); 
    }) 
    }